“He said he was a very miserable creature, that he had earnestly sought death during his sojourn upon the earth, but that he could not die, and his mission was to destroy the souls of men. I rebuked him in the name of the Lord Jesus Christ.”

This is further corroborated by a 1919 manuscript which included a reference to an attack by a hairy, talking humanoid described as Cain.

As far as Bigfoot lore goes, this theory provides an out for at least one major hole. Bigfoot would be an immortal creature and not a new species which would explain why he’s so elusive. It’s far more of a challenge to catch one man than a thriving, natural animal bloodline.